Well, you can make a 12 volt power supply very cheaply and easily!
I needed a 12 volt power supply for my project, the SSTC (Solid State Tesla Coil), and also made this instructable because it might be use full to someone...
Step 1: Things that you will need...
- Piece of veroboard
- Four 1N4001 diodes
- LM7812 regulator
- Transformer that has an output of 14v - 35v AC with an output current between 100mA to 1A, depending how much power you will need. (I found a 16v 200mA transformer in a broken alarm clock.)
- 1000uF - 4700uF capacitor
- 1uF capacitor
- Two 100nF capacitors
- Jumper wires (I used some plain wire as jumper wires)
- Heatsink (optional)
Step 2: And the tools...
- Soldering iron
- Wire cutters
- Wire strippers
- A thing you can cut veroboard tracks.
- Hot glue (To hold components down and make the power supply physically strong and sturdy.)
- And some other tools that you might find helpful.
Step 3: Schematic and others...
Datasheet for LM78XX
If you are going to pull out about 1 amp from this power supply, you will need a heatsink for the regulator, otherwise it will generate very high temperatures and possibly burn out...
However, if you are just going to pull out a few hundred milliamps (lower than 500mA) from it, you won't need a heatsink for the regulator, but it may get a little bit warm.
Also, heres the schematic...
I also add in an LED to make sure the power supply is working. You can add in an LED if you want.